import java.util.Scanner;
public class Task04 {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		float x;
		int counter = 0;
		
		do {
			x = sc.nextFloat();
			if (x >= 0 && x%2 == 0) {
				counter++;
			}
		} while (x >= 0);
		
		System.out.println(counter);
		sc.close();
		
		
		

	}

}
